Are you getting “Updating Aperture Videos Events” and iMovie just hanging?

Open your Aperture Library. (By clicking on Show the Package Contents)


Delete iMovie->Thumbnails and iLifeShared

I would also recommend running
Onyx to clean your caches and repair permissions.

Don’t see your Aperture library in iMovie?


Open Aperture, > Preferences, and click Previews. In the “Share previews with iLife and iWork”